1. Field of the Invention
The present invention relates to wheel end assemblies for motor vehicles, and more particularly to an arrangement for aligning a centerline of a steering knuckle in a live spindle wheel end assembly in a steering beam axle assembly for use in a motor vehicle.
2. Description of the Prior Art
Motor vehicle wheel end assemblies may be divided into two general categoriesxe2x80x94dead spindles and live spindles. The dead spindle wheel end assemblies generally include a non-rotatable spindle extending outward from a mounting member, such as a steering knuckle, which is typically attached to a vehicle chassis. A wheel hub including a wheel-mounting flange is supported for rotation on the spindle by bearings. A wheel and tire assembly may then be attached to the wheel-mounting flange so that the wheel is mounted coaxially with the spindle and wheel hub.
Wheel end assemblies including a dead spindle can be used on a part time four wheel drive vehicle that is free running when the driver has selected two-wheel drive mode. The wheel end assembly receives torque from a drive axle when the driver has selected four-wheel drive mode, wherein a bore is formed through the spindle to accept a drive axle that originates at a differential. The drive axle is coupled to rotate with a first gear or member of a hub lock mechanism and the wheel hub is coupled to rotate with a second gear or member of the hub lock mechanism. The hub lock mechanism is designed to selectively couple the drive axle to the wheel hub by engaging the first hub lock member with the second hub lock member thereby allowing the drive axle to transmit torque to the wheel hub and ultimately to the vehicle wheel/tire assembly mounted thereon. For a driving/steering axle, a constant velocity universal joint is also provided between the differential and the wheel end assembly.
The live spindle wheel end assemblies generally include a spindle, which is supported for rotation by bearings within a bore formed in a mounting member such as a steering knuckle, which is attached to a vehicle chassis. A wheel mounting flange is formed in the spindle or is attached thereto by welding or another suitable method. To provide the live spindle wheel end assembly for use on a four wheel drive vehicle that is free running when the driver has selected two-wheel drive mode and that receives torque from a drive axle when the driver has selected four-wheel drive mode, a bore is formed through the spindle to accept a drive axle that originates at a differential. The drive axle is coupled to rotate with a first gear or member of a hub lock mechanism and the spindle is coupled to rotate with a second gear or member of the hub lock mechanism. The hub lock mechanism is designed to selectively couple the drive axle to the spindle by engaging the first hub lock member with the second hub lock member thereby allowing the drive axle to transmit torque to the spindle, and ultimately to the vehicle wheel/tire assembly. For a driving/steering axle, a universal joint, such as constant velocity joint, must also be provided between the differential and the wheel end assembly.
In general, the live spindle wheel end assemblies are supported for rotation within the bore of the mounting member by bearing assemblies including an inner race, an outer race, and a plurality of rolling elements circumferentially spaced between the inner and outer races. These bearing assemblies are typically slid onto the outer surface of the spindle and held in place by a lock-nut or another suitable retainer. However, it has been found that the inner bearing race may be formed directly in the outer surface of the spindle, thereby eliminating the need to provide a bearing assembly including a separate inner bearing race. Such a bearing assembly provides numerous advantages such as ease of assembly and disassembly, ease of service, less unsprung vehicle weight, and potentially lower cost. However, the use of these wheel end assemblies having the inner bearing races formed directly on the spindle has been limited to two-wheel drive applications. With the increasing popularity of four-wheel drive vehicles, there has been found a need to provide such a wheel end assembly that is capable of receiving a hub lock mechanism to selectively drivingly couple a drive axle to the spindle so that torque may be transmitted from the drive axle through the spindle and to a road wheel mounted thereon.
As well known to those skilled in the art, in order for the live spindle wheel end assembly to operate properly (i.e., without excessive load, friction and vibration), a centerline of the steering knuckle, coinciding with an axis of rotation of the spindle, has to be aligned with an axis of rotation of the drive axle shaft. Steering knuckle centerline misalignment adversely affects spindle bearings and universal joint durability and performance, and generates unwanted vibration and noise. However, existing designs of the live spindle wheel end assemblies do not allow for adjustment (aligning) of the steering knuckle centerline and the drive axle shaft axis of rotation. Currently, alignment of the steering knuckle centerline and the drive axle shaft axis is defined solely by the tolerance stack-up of the components of the wheel end assembly.
Thus, there is a need for a live spindle wheel end assembly that includes a steering knuckle centering adjuster for aligning a centerline of a steering knuckle.
The present invention provides a novel arrangement of a wheel end assembly in a steering beam axle for use in a motor vehicle. The wheel end assembly in accordance with the present invention comprises a tube yoke attached to an axle tube defining an axle centerline, a steering knuckle defining a steering knuckle centerline, a driving axle shaft rotatably disposed in the axle tube, a live spindle rotatably supported by the steering knuckle, a stub shaft extending through the live spindle and rotatably coupled thereto, and a universal joint connecting the driving axle shaft and the stub shaft. The steering knuckle is pivotally coupled to the tube yoke through at least one swivel joint assembly defining a steering axis.
Preferably, the tube yoke has vertically spaced upper and lower arms, and the steering knuckle has an upper flange disposed adjacent the upper arm of the tube yoke and a lower flange disposed adjacent the lower arm of the tube yoke. The upper arm of the tube yoke is pivotally connected to the upper flange of the steering knuckle through an upper swivel joint assembly, while the lower arm of the tube yoke is pivotally connected to the lower flange of the steering knuckle through a lower swivel joint assembly.
The wheel end assembly further includes a knuckle centering adjuster for adjusting the knuckle centerline by selectively moving said steering knuckle relative to said tube yoke along said steering axis in order to align the knuckle centerline to the axle centerline. Preferably, the steering knuckle centering adjuster includes an adjusting sleeve threadedly positioned in a bore in the lower flange of the steering knuckle, wherein the adjusting sleeve positively engages a stud extending from the lower swivel joint assembly, and wherein rotation of the adjusting sleeve within the bore in the lower flange of the steering knuckle causes the steering knuckle to move relative to the lower swivel joint assembly along the steering axis thereby resulting in an adjustment of the steering knuckle centerline by aligning the steering knuckle centerline to the axle centerline.
Therefore, the wheel end assembly with the steering knuckle centering adjuster in accordance with the present invention represents a novel arrangement of the wheel end assembly that provides less vibration, and improves durability of spindle bearings and universal joints over the current design.